Identification of MyD88 as a novel target of miR-155, involved in negative regulation of Helicobacter pylori -induced inflammation

MicroRNAs Regulate the Expression of Genes Related to the Innate Immune and Inflammatory Response in Rabbits Infected with Lagovirus europaeus GI.1 and GI.2 Genotypes

MicroRNAs (miR) are a group of small, non-coding RNAs of 17-25 nucleotides that regulate gene expression at the post-transcriptional level. Dysregulation of miRNA expression or function may contribute to abnormal gene expression and signaling pathways, leading to disease pathology. Lagovirus europaeus (L. europaeus) causes severe disease in rabbits called rabbit hemorrhagic disease (RHD). The symptoms of liver, lung, kidney, and spleen degeneration observed during RHD are similar to those of acute liver failure (ALF) and multi-organ failure (MOF) in humans. In this study, we assessed the expression of miRs and their target genes involved in the innate immune and inflammatory response. Also, we assessed their potential impact on pathways in L. europaeus infection-two genotypes (GI.1 and GI.2)-in the liver, lungs, kidneys, and spleen. The expression of miRs and target genes was determined using quantitative real-time PCR (qPCR). We assessed the expression of miR-155 (MyD88, TAB2, p65, NLRP3), miR-146a (IRAK1, TRAF6), miR-223 (TLR4, IKKα, NLRP3), and miR-125b (MyD88). We also examined biomarkers of inflammation: IL-1β, IL-6, TNF-α, and IL-18 in four tissues at the mRNA level. Our study shows that the main regulators of the innate immune and inflammatory response in L. europaeus/GI.1 and GI.2 infection, as well as RHD, are miR-155, miR-223, and miR-146a. During infection with L. europaeus/RHD, miR-155 has both pro- and anti-inflammatory effects in the liver and anti-inflammatory effects in the kidneys and spleen; miR-146a has anti-inflammatory effects in the liver, lungs and kidneys; miR-223 has anti-inflammatory effects in all tissues; however, miR-125b has anti-inflammatory effects only in the liver. In each case, such an effect may be a determinant of the pathogenesis of RHD. Our research shows that miRs may regulate three innate immune and inflammatory response pathways in L. europaeus infection. However, the result of this regulation may be influenced by the tissue microenvironment. Our research shows that infection of rabbits with L. europaeus/GI.1 and GI.2 genotypes causes an overexpression of two critical acute phase cytokines: IL-6 in all examined tissues and TNF-α (in the liver, lungs, and spleen). IL-1β was highly expressed only in the lungs after L. europaeus infection. These facts indicate a strong and rapid involvement of the local innate immune and inflammatory response in L. europaeus infection-two genotypes (GI.1 and GI.2)-and in the pathogenesis of RHD. Profile of biomarkers of inflammation in rabbits infected with L. europaeus/GI.1 and GI.2 genotypes are similar regarding the nature of changes but are different for individual tissues. Therefore, we propose three inflammation profiles for L. europaeus infection for both GI.1 and GI.2 genotypes (pulmonary, renal, liver, and spleen).

The ability of microRNAs to regulate the immune response in ischemia/reperfusion inflammatory pathways

MicroRNAs play a crucial role in regulating the immune responses induced by ischemia/reperfusion injury. Through their ability to modulate gene expression, microRNAs adjust immune responses by targeting specific genes and signaling pathways. This review focuses on the impact of microRNAs on the inflammatory pathways triggered during ischemia/reperfusion injury and highlights their ability to modulate inflammation, playing a critical role in the pathophysiology of ischemia/reperfusion injury. Dysregulated expression of microRNAs contributes to the pathogenesis of ischemia/reperfusion injury, therefore targeting specific microRNAs offers an opportunity to restore immune homeostasis and improve patient outcomes. Understanding the complex network of immunoregulatory microRNAs could provide novel therapeutic interventions aimed at attenuating excessive inflammation and preserving tissue integrity.

Grade C Molar-Incisor Pattern Periodontitis in Young Adults: What Have We Learned So Far?

Grade C molar-incisor pattern periodontitis (C-MIP) is a disease that affects specific teeth with an early onset and aggressive progression. It occurs in systemically healthy patients, mostly African descendants, at an early age, with familial involvement, minimal biofilm accumulation, and minor inflammation. Severe and rapidly progressive bone loss is observed around the first molars and incisors. This clinical condition has been usually diagnosed in children and young adults with permanent dentition under 30 years of age. However, this disease can also affect the primary dentition, which is not as frequently discussed in the literature. Radiographic records have shown that most patients diagnosed in the permanent dentition already presented disease signs in the primary dentition. A hyperresponsive immunological profile is observed in local (gingival crevicular fluid-GCF) and systemic environments. Siblings have also displayed a heightened inflammatory profile even without clinical signs of disease. A. actinomycetemcomitans has been classified as a key pathogen in C-MIP in both dentitions. Scaling and root planning associated with systemic antibiotics is the current gold standard to treat C-MIP, leading to GCF biomarker reduction, some systemic inflammatory response modulation and microbiome profile changes to a healthy-site profile. Further studies should focus on other possible disease-contributing risk factors.

MicroRNAs in Helicobacter pylori-infected gastric cancer: Function and clinical application

Gastric cancer (GC) is the leading cause of cancer-related death worldwide, and it is associated with a combination of genetic, environmental, and microbial risk factors. Helicobacter pylori (H. pylori) is classified as a type I carcinogen, however, the exact regulatory mechanisms underlying H. pylori-induced GC are incompletely defined. MicroRNAs (miRNAs), one of small non-coding RNAs, negatively regulate gene expression through binding to their target genes. Dysregulation of miRNAs is crucial in human cancer. A noteworthy quantity of aberrant miRNAs induced by H. pylori through complex regulatory networks have been identified. These miRNAs substantially affect genetic instability, cell proliferation, apoptosis, invasion, metastasis, autophagy, chemoresistance, and the tumor microenvironment, leading to GC development and progression. Importantly, some H. pylori-associated miRNAs hold promise as therapeutic tools and biomarkers for GC prevention, diagnosis, and prognosis. Nonetheless, clinical application of miRNAs remains in its infancy with multiple issues, including sensitivity and specificity, stability, reliable delivery systems, and off-target effects. Additional research on the specific molecular mechanisms and more clinical data are still required. This review investigated the biogenesis, regulatory mechanisms, and functions of miRNAs in H. pylori-induced GC, offering novel insights into the potential clinical applications of miRNA-based therapeutics and biomarkers.

The novel fish miRNA, Soc-miR-118, functions as a negative regulator in NF-κB-mediated inflammation by targeting IL-6 in teleost fish

Inflammation is initiated as a protective response of the organism to remove invading bacterial and initiate the healing process. Prolonged inflammation and excessive production of inflammatory cytokines lead to inflammatory disorders or autoimmune diseases. Thus, different layers of negative regulators are needed to achieve balances between protective immunity and inflammatory pathology. Accumulating evidences show that miRNAs act as significant and multifunctional regulators involved in regulating networks of host-pathogen interactions. However, the functions and mechanisms of miRNAs in directly targeting and regulating inflammatory cytokines remains largely unknown in lower vertebrates. In this study, we report a novel miRNA, Soc-miR-118, identified from Sciaenops ocellatus, which plays a negative role in antibacterial immunity by regulating Interleukin-6 (IL-6). Specifically, we found that Soc-miR-118 directly targets IL-6 and suppresses the production of inflammatory cytokines through the NF-κB signaling pathway, thereby avoiding excessive inflammatory response. Particularly, the mechanism by which Soc-miR-118 regulates IL-6 expression also exist in other fish, suggesting that the miRNA in fish has evolutionarily conserved regulatory systems. The collective results that Soc-miR-118 acts as a negative regulator involved in host antibacterial immunity through directly regulating inflammatory cytokines, will greatly enrich the intricate networks of host-pathogen interaction in lower vertebrates.

Exosomal microRNAs as biomarkers for viral replication in tofacitinib-treated rheumatoid arthritis patients with hepatitis C

Notwithstanding recent advances in direct antiviral specialists (DAAs) for hepatitis C infection (HCV), it is yet a pervasive overall issue in patients with rheumatoid arthritis (RA). Exosomal microRNAs (miRNAs) is associated with HCV infection. However, it remains unknown how miRNAs respond following biologic disease-modifying antirheumatic drug (bDMARD) and targeted synthetic DMARD (tsDMARD) treatment in HCV patients with RA. We prospectively recruited RA patients taking anti-tumor necrosis factor-α (TNF-α) inhibitors rituximab (RTX) and tofacitinib. The serum hepatitis C viral load was measured using real-time quantitative reverse transcriptase PCR before and 6 months after bDMARD and tsDMARD therapy. HCV RNA replication activity was measured using an HCV-tricistronic replicon reporter system, and quantitative analysis of hsa-mir-122-5p and hsa-mir-155-5p in patients was performed using quantitative PCR. HCV RNA replication in hepatocytes was not affected by tofacitinib or TNF-α inhibitor treatment. Hsa-mir-155-5p and hsa-mir-122-5p were significantly expanded in RA patients with HCV as compared with those without HCV. We observed a dramatic increase in hsa-mir-122-5p and a decrease in hsa-mir-155-5p expression levels in patients taking RTX in comparison with other treatments. Finally, a reduction in hsa-mir-122-5p and an increase in hsa-mir-155-5p were observed in a time-dependent manner after tofacitinib and DAA therapy in RA-HCV patients. These results showed that hsa-mir-155-5p and hsa-mir-122-5p were significantly increased in RA-HCV patients as compared with those without HCV after taking tofacitinib. Hsa-mir-155-5p and hsa-mir-122-5p may be potential biomarkers for treatment efficacy in RA patients with HCV.

MicroRNA as a potential biomarker for systemic lupus erythematosus: pathogenesis and targeted therapy

Systemic lupus erythematosus (SLE) is an autoimmune disease associated with hyperactive innate and adaptive immune systems that cause dermatological, cardiovascular, renal, and neuropsychiatric problems in patients. SLE's multifactorial nature and complex pathogenesis present significant challenges in its clinical classification. In addition, unpredictable treatment responses in patients emphasize the need for highly specific and sensitive SLE biomarkers that can assist in understanding the exact pathogenesis and, thereby, lead to the identification of novel therapeutic targets. Recent studies on microRNA (miRNA), a non-coding region involved in the regulation of gene expression, indicate its importance in the development of the immune system and thus in the pathogenesis of various autoimmune disorders such as SLE. miRNAs are fascinating biomarker prospects for SLE categorization and disease monitoring owing to their small size and high stability. In this paper, we have discussed the involvement of a wide range of miRNAs in the regulation of SLE inflammation and how their modulation can be a potential therapeutic approach.

The potential role of miRNA in regulating macrophage polarization

Macrophage polarization is a dynamic process determining the outcome of various physiological and pathological situations through inducing pro-inflammatory responses or resolving inflammation via exerting anti-inflammatory effects. The miRNAs are epigenetic regulators of different biologic pathways that target transcription factors and signaling molecules to promote macrophage phenotype transition and regulate immune responses. Modulating the macrophage activation, differentiation, and polarization by miRNAs is crucial for immune responses in response to microenvironmental signals and under various physiological and pathological conditions. In term of clinical significance, regulating macrophage polarization via miRNAs could be utilized for inflammation control. Also, understanding the role of miRNAs in macrophage polarization can provide insights into diagnostic strategies associated with dysregulated miRNAs and for developing macrophage-centered therapeutic methods. In this case, targeting miRNAs to further regulate of macrophage polarization may become an efficient strategy for treating immune-associated disorders. The current review investigated and categorized various miRNAs directly or indirectly involved in macrophage polarization by targeting different transcription factors and signaling pathways. In addition, prospects for regulating macrophage polarization via miRNA as a therapeutic choice that could be implicated in various pathological conditions, including cancer or inflammation-mediated injuries, were discussed.

Trophoblast Cell Function in the Antiphospholipid Syndrome

Antiphospholipid syndrome (APS) is a complex thrombo-inflammatory autoimmune disease characterized by the presence of antiphospholipid antibodies (aPL). Women with APS are at high risk of recurrent early pregnancy loss as well as late obstetrical complications-premature birth due to placental insufficiency or severe preeclampsia. Accumulating evidence implies that vascular thrombosis is not the only pathogenic mechanism in obstetric APS, and that the direct negative effect of aPL on the placental cells, trophoblast, plays a major role. In this review, we summarize the current findings regarding the potential mechanisms involved in aPL-induced trophoblast dysfunction. Introduction on the APS and aPL is followed by an overview of the effects of aPL on trophoblast-survival, cell function and aPL internalization. Finally, the implication of several non-coding RNAs in pathogenesis of obstetric APS is discussed, with special emphasis of their possible role in trophoblast dysfunction and the associated mechanisms.

Exploring the impact of miR-128 in inflammatory diseases: A comprehensive study on autoimmune diseases

microRNAs (miRNAs) play a crucial role in various biological processes, including immune system regulation, such as cell proliferation, tolerance (central and peripheral), and T helper cell development. Dysregulation of miRNA expression and activity can disrupt immune responses and increase susceptibility to neuroimmune disorders. Conversely, miRNAs have been shown to have a protective role in modulating immune responses and preventing autoimmunity. Specifically, reducing the expression of miRNA-128 (miR-128) in an Alzheimer's disease (AD) mouse model has been found to improve cognitive deficits and reduce neuropathology. This comprehensive review focuses on the significance of miR-128 in the pathogenesis of neuroautoimmune disorders, including multiple sclerosis (MS), AD, Parkinson's disease (PD), Huntington's disease (HD), epilepsy, as well as other immune-mediated diseases such as inflammatory bowel disease (IBD) and rheumatoid arthritis (RA). Additionally, we present compelling evidence supporting the potential use of miR-128 as a diagnostic or therapeutic biomarker for neuroimmune disorders. Collectively, the available literature suggests that targeting miR-128 could be a promising strategy to alleviate the behavioral symptoms associated with neuroimmune diseases. Furthermore, further research in this area may uncover new insights into the molecular mechanisms underlying these disorders and potentially lead to the development of novel therapeutic approaches.

The TLR/MyD88 signalling cascade in inflammation and gastric cancer: the immune regulatory network of Helicobacter pylori

Helicobacter pylori-induced chronic gastritis represents a well-established risk factor for gastric cancer (GC). However, the mechanism by which chronic inflammation caused by H. pylori induces the development of GC is unclear. H. pylori can influence host cell signalling pathways to induce gastric disease development and mediate cancer promotion and progression. Toll-like receptors (TLRs), as pattern recognition receptors (PRRs), play a key role in the gastrointestinal innate immune response, and their signalling has been implicated in the pathogenesis of an increasing number of inflammation-associated cancers. The core adapter myeloid differentiation factor-88 (MyD88) is shared by most TLRs and functions primarily in H. pylori-triggered innate immune signalling. MyD88 is envisioned as a potential target for the regulation of immune responses and is involved in the regulation of tumourigenesis in a variety of cancer models. In recent years, the TLR/MyD88 signalling pathway has received increasing attention for its role in regulating innate and adaptive immune responses, inducing inflammatory activation and promoting tumour formation. In addition, TLR/MyD88 signalling can manipulate the expression of infiltrating immune cells and various cytokines in the tumour microenvironment (TME). In this review, we discuss the pathogenetic regulatory mechanisms of the TLR/MyD88 signalling cascade pathway and its downstream molecules in H. pylori infection-induced-associated GC. The focus is to elucidate the immunomolecular mechanisms of pathogen recognition and innate immune system activation of H. pylori in the TME of inflammation-associated GC. Ultimately, this study will provide insight into the mechanism of H. pylori-induced chronic inflammation-induced GC development and provide thoughts for GC prevention and treatment strategies.

Comprehensive insight into altered host cell-signaling cascades upon Helicobacter pylori and Epstein-Barr virus infections in cancer

Cancer is characterized by mutagenic events that lead to disrupted cell signaling and cellular functions. It is one of the leading causes of death worldwide. Literature suggests that pathogens, mainly Helicobacter pylori and Epstein-Barr virus (EBV), have been associated with the etiology of human cancer. Notably, their co-infection may lead to gastric cancer. Pathogen-mediated DNA damage could be the first and crucial step in the carcinogenesis process that modulates numerous cellular signaling pathways. Altogether, it dysregulates the metabolic pathways linked with cell growth, apoptosis, and DNA repair. Modulation in these pathways leads to abnormal growth and proliferation. Several signaling pathways such RTK, RAS/MAPK, PI3K/Akt, NFκB, JAK/STAT, HIF1α, and Wnt/β-catenin are known to be altered in cancer. Therefore, this review focuses on the oncogenic roles of H. pylori, EBV, and its associated signaling cascades in various cancers. Scrutinizing these signaling pathways is crucial and may provide new insights and targets for preventing and treating H. pylori and EBV-associated cancers.

Oxidized low-density lipoprotein regulates macrophage polarization in atherosclerosis

Atherosclerosis is the pathological basis of acute cardiovascular and cerebrovascular diseases. Oxidized LDL has been recognized as a major atherogenic factor in the vessel wall for decades. A growing body of evidence suggests that oxidized LDL modulates macrophage phenotypes in atherosclerosis. This article reviews the research progress on the regulation of macrophage polarization by oxidized LDL. Mechanistically, oxidized LDL induces macrophage polarization via cell signaling, metabolic reprogramming, epigenetic regulation, and intercellular regulation. This review is expected to provide new targets for the treatment of atherosclerosis.

Roles of the miR-155 in Neuroinflammation and Neurological Disorders: A Potent Biological and Therapeutic Target

Neuroinflammation plays a crucial role in the development and progression of neurological disorders. MicroRNA-155 (miR-155), a miR is known to play in inflammatory responses, is associated with susceptibility to inflammatory neurological disorders and neurodegeneration, including Alzheimer's disease, Parkinson's disease, multiple sclerosis, and amyotrophic lateral sclerosis as well as epilepsy, stroke, and brain malignancies. MiR-155 damages the central nervous system (CNS) by enhancing the expression of pro-inflammatory cytokines, like IL-1β, IL-6, TNF-α, and IRF3. It also disturbs the blood-brain barrier by decreasing junctional complex molecules such as claudin-1, annexin-2, syntenin-1, and dedicator of cytokinesis 1 (DOCK-1), a hallmark of many neurological disorders. This review discusses the molecular pathways which involve miR-155 as a critical component in the progression of neurological disorders, representing miR-155 as a viable therapeutic target.

The regulation roles of miRNAs in Helicobacter pylori infection

Helicobacter pylori is a kind of Gram-negative bacteria that parasitizes on human gastric mucosa. Helicobacter pylori infection is very common in human beings, which often causes gastrointestinal diseases, including chronic gastritis, duodenal ulcer and gastric cancer. MicroRNAs are a group of endogenous non-coding single stranded RNAs, which play an important role in cell proliferation, differentiation, autophagy, apoptosis and inflammation. In recent years, relevant studies have found that the expression of microRNA is changed after Helicobacter pylori infection, and then regulate the biological process of host cells. This paper reviews the regulation role of microRNAs on cell biological behavior through different signal pathways after Helicobacter pylori infection.

Targeting epigenetic regulators for inflammation: Mechanisms and intervention therapy

Emerging evidence indicates that resolution of inflammation is a critical and dynamic endogenous process for host tissues defending against external invasive pathogens or internal tissue injury. It has long been known that autoimmune diseases and chronic inflammatory disorders are characterized by dysregulated immune responses, leading to excessive and uncontrol tissue inflammation. The dysregulation of epigenetic alterations including DNA methylation, posttranslational modifications to histone proteins, and noncoding RNA expression has been implicated in a host of inflammatory disorders and the immune system. The inflammatory response is considered as a critical trigger of epigenetic alterations that in turn intercede inflammatory actions. Thus, understanding the molecular mechanism that dictates the outcome of targeting epigenetic regulators for inflammatory disease is required for inflammation resolution. In this article, we elucidate the critical role of the nuclear factor-κB signaling pathway, JAK/STAT signaling pathway, and the NLRP3 inflammasome in chronic inflammatory diseases. And we formulate the relationship between inflammation, coronavirus disease 2019, and human cancers. Additionally, we review the mechanism of epigenetic modifications involved in inflammation and innate immune cells. All that matters is that we propose and discuss the rejuvenation potential of interventions that target epigenetic regulators and regulatory mechanisms for chronic inflammation-associated diseases to improve therapeutic outcomes.

Combinatorial microRNA Loading into Extracellular Vesicles for Increased Anti-Inflammatory Efficacy

Extracellular vesicles (EVs) have emerged as promising therapeutic entities in part due to their potential to regulate multiple signaling pathways in target cells. This potential is derived from the broad array of constituent and/or cargo molecules associated with EVs. Among these, microRNAs (miRNAs) are commonly implicated as important and have been associated with a wide variety of EV-induced biological phenomena. While controlled loading of single miRNAs is a well-documented approach for enhancing EV bioactivity, loading of multiple miRNAs has not been fully leveraged to maximize the potential of EV-based therapies. Here, an established approach to extrinsic nucleic acid loading of EVs, sonication, was utilized to load multiple miRNAs in HEK293T EVs. Combinations of miRNAs were compared to single miRNAs with respect to anti-inflammatory outcomes in assays of increasing stringency, with the combination of miR-146a, miR-155, and miR-223 found to have the most potential amongst the tested groups.

miR-125-3p and miR-276b-3p Regulate the Spermatogenesis of Bactrocera dorsalis by Targeting the orb2 Gene

Bactrocera dorsalis is considered a major threat to horticultural crops. It has evolved resistance against insecticides. It is believed that development of new methods is highly desirable to control this destructive agricultural pest. Sterile insect technique is emerging as a potential tool to control this insect pest by reducing their reproductive ability. Here we report that orb2 has high expression in the testis of B. dorsalis which is the target of miR-125-3p and miR-276b-3p and plays a critical role in the spermatogenesis. Dual luciferase reporter assay using HEKT293 cells demonstrates that orb2 gene is downregulated by miR-125-3p and miR-276b-3p and is a common target of these miRNAs. Dietary treatment of adult male flies separately and in combination of agomir-125-3p (Ago-125-3p) and agomir-276b-3p (Ago-276b-3p) significantly downregulated the mRNA of orb2. The combined treatments of agomirs suppressed the level of mRNA of orb2 significantly more than any single treatment. Altered expression of miR-125-3p and miR-276b-3p significantly decreased the total and live spermatozoa in the testis which ultimately caused reduction in male fertility. Furthermore, we demonstrate that miR-125-3p, miR-276b-3p, and orb2 dsRNA are the novel agents that could be used in a genetic-based sterile insect technique (SIT) to control the B. dorsalis.

Helicobacter pylori Infection Mediates Inflammation and Tumorigenesis-Associated Genes Through miR-155-5p: An Integrative Omics and Bioinformatics-Based Investigation

Helicobacter pylori (H. pylori) is a major human pathogenic bacterium that survives in the gastric mucosa. The aim of this study is to evaluate the expression of the target gene network of miR-155-5p in H. pylori-related gastritis using a combination of public gene expression datasets and web-based platforms. To evaluate the expression of genes related to gastritis, we used two datasets from Gene Expression Omnibus (GEO) database. Then, we determined the overlaps between the predicted miR-155-5p target genes and gastritis-dysregulated GEO datasets genes; in the next step, we identified the possible miR-155-5p target-DEGs (Target-Differentially Expressed Genes). Also, we performed multiple bioinformatics analyses to identify the most important targets and downstream pathways associated with this miRNA. Using the UCSC cancer genomic browser analysis tool, we investigated the expression of hub genes in relation to gastric cancer and H. pylori infection, as well as the potential role of hub genes in gastritis, inflammation, and cancer. In this regard, 28 differentially expressed target genes of miR-155-5p were identified. Most of the captured target genes were correlated with the host immune response and inflammation. Based on the specific patterns of expression in gastritis and cancer, CD9, MST1R, and ADAM10 were candidates for the most probable targets of miR-155-5p. Although the focus of this study is primarily on bioinformatics, we think that our findings should be experimentally validated before they can be used as potential therapeutic and diagnostic tools.

Understanding microRNAs in the Context of Infection to Find New Treatments against Human Bacterial Pathogens

The development of RNA-based anti-infectives has gained interest with the successful application of mRNA-based vaccines. Small RNAs are molecules of RNA of <200 nucleotides in length that may control the expression of specific genes. Small RNAs include small interference RNAs (siRNAs), Piwi-interacting RNAs (piRNAs), or microRNAs (miRNAs). Notably, the role of miRNAs on the post-transcriptional regulation of gene expression has been studied in detail in the context of cancer and many other genetic diseases. However, it is also becoming apparent that some human miRNAs possess important antimicrobial roles by silencing host genes essential for the progress of bacterial or viral infections. Therefore, their potential use as novel antimicrobial therapies has gained interest during the last decade. The challenges of the transport and delivery of miRNAs to target cells are important, but recent research with exosomes is overcoming the limitations in RNA-cellular uptake, avoiding their degradation. Therefore, in this review, we have summarised the latest developments in the exosomal delivery of miRNA-based therapies, which may soon be another complementary treatment to pathogen-targeted antibiotics that could help solve the problem caused by multidrug-resistant bacteria.

The role of non-coding RNA in the diagnosis and treatment of Helicobacter pylori-related gastric cancer, with a focus on inflammation and immune response

Helicobacter pylori (H. pylori) is one of the globally recognized causative factors of gastric cancer (GC). Currently, no definite therapy and drugs for H. pylori-related GC have been widely acknowledged although H. pylori infection could be eradicated in early stage. Inflammation and immune response are spontaneous essential stages during H. pylori infection. H pylori may mediate immune escape by affecting inflammation and immune response, leading to gastric carcinogenesis. As an important component of transcriptome, non-coding RNAs (ncRNAs) have been proven to play crucial roles in the genesis and development of H. pylori-induced GC. This review briefly described the effects of ncRNAs on H. pylori-related GC from the perspective of inflammation and immune response, as well as their association with inflammatory reaction and immune microenvironment. We aim to explore the potential of ncRNAs as markers for the early diagnosis, prognosis, and treatment of H. pylori-related GC. The ncRNAs involved in H. pylori-related GC may all hold promise as novel therapeutic targets for immunotherapy.

NOP56 negatively regulates MyD88-mediated NF-κB signaling in miiuy croaker, Miichthys miiuy

MyD88 is a critical adaptor in the TLRs signaling pathway, which can activate NF-κB signaling pathway and promote proinflammatory cytokines production. However, the molecular mechanisms that modulate MyD88 expression, especially in teleost, remain largely unknown. In this study, we showed that NOP56 serve as a negative regulator of the MyD88-mediated NF-κB signaling pathway. NOP56 overexpression inhibited the protein expression of MyD88. Whereas, siRNA knockdown of NOP56 had opposite effect. Furthermore, we found that the NOSIC domain is responsible for the suppressive effect of NOP56 in MyD88 expression at protein level. Therefore, we identified NOP56 as a negative regulator of MyD88-mediated NF-κB signaling by inhibiting MyD88 expression and provided new insight into the regulation mechanism in teleost fish.

Inflammatory Biomarkers in Addictive Disorders

Substance use disorders are a group of diseases that are associated with social, professional, and family impairment and that represent a high socio-economic impact on the health systems of countries around the world. These disorders present a very complex diagnosis and treatment regimen due to the lack of suitable biomarkers supporting the correct diagnosis and classification and the difficulty of selecting effective therapies. Over the last few years, several studies have pointed out that these addictive disorders are associated with systemic and central nervous system inflammation, which could play a relevant role in the onset and progression of these diseases. Therefore, identifying different immune system components as biomarkers of such addictive disorders could be a crucial step to promote appropriate diagnosis and treatment. Thus, this work aims to provide an overview of the immune system alterations that may be biomarkers of various addictive disorders.

Targeting Toll-like Receptor (TLR) Pathways in Inflammatory Arthritis: Two Better Than One?

Inflammatory arthritis is a cluster of diseases caused by unregulated activity of the immune system. The lost homeostasis is followed by the immune attack of one’s self, what damages healthy cells and tissues and leads to chronic inflammation of various tissues and organs (e.g., joints, lungs, heart, eyes). Different medications to control the excessive immune response are in use, however, drug resistances, flare-reactions and adverse effects to the current therapies are common in the affected patients. Thus, it is essential to broaden the spectrum of alternative treatments and to develop disease-modifying drugs. In the last 20 years, the involvement of the innate immune receptors TLRs in inflammatory arthritis has been widely investigated and targeting either the receptor itself or the proteins in the downstream signalling cascades has emerged as a promising therapeutic strategy. Yet, concerns about the use of pharmacological agents that inhibit TLR activity and may leave the host unprotected against invading pathogens and toxicity issues amid inhibition of downstream kinases crucial in various cellular functions have arisen. This review summarizes the existing knowledge on the role of TLRs in inflammatory arthritis; in addition, the likely druggable related targets and the developed inhibitors, and discusses the pros and cons of their potential clinical use.

Opposite effects of miR-155 in the initial and later stages of lipopolysaccharide (LPS)-induced inflammatory response

Although microRNA-155 (miR-155) is considered a pro-inflammatory mediator, cumulative evidence indicates that it also has anti-inflammatory effects in macrophages and dendritic cells. In this study, we identified the dramatic expression changes of more than half of potential miR-155-targeted genes upon lipopolysaccharide (LPS) stimulation; 223 genes were down-regulated and 85 genes were up-regulated, including suppressor of cytokine signaling 1 (SOCS1) and transforming growth factor-β-activated kinase 1-binding protein 2 (TAB2), two well-known genes involved in miR-155-mediated regulation of the Toll-like receptor 4 (TLR4) signaling pathway. We also found that miR-155 acted as an anti-inflammatory mediator in the initial stage of LPS-induced inflammatory response mainly through repressing TAB2 protein translation, and as a pro-inflammatory mediator by down-regulating SOCS1 in the later stage. Meanwhile, overexpression of TAB2 3' untranslated region (UTR) in macrophages promoted the development of endotoxin tolerance by competing for binding with miR-155, which resulted in an elevated expression level of SOCS1 protein. These findings provide new insights for understanding the regulatory mechanisms in fine-tuning of LPS-induced innate immune response.

Genome-Wide MicroRNA Analysis of Peripheral Blood Mononuclear Cells Reveals Elevated miR-142-3p Expression as a Potential Biomarker for Secondary Syphilis

Background

Treponema pallidum subspecies pallidum (T. pallidum) infection induces significant immune responses, resulting in tissue damage. Gene expression plays an essential role in regulating the progression of syphilis infection. However, little is known about the regulatory role of microRNAs (miRNAs) in the immune response to T. pallidum infection. Here, we analyze the differential expression of miRNAs in peripheral blood mononuclear cells (PBMCs) between untreated secondary syphilis patients and healthy controls and study the correlation between miRNA expression and clinical features with bioinformatics.

Methods

The expression profile of miRNAs was measured by microarray analysis in PBMCs of untreated secondary syphilis patients and healthy controls. Weighted Gene Coexpression Network Analysis (WGCNA) was used to construct the expression of miRNAs and the clinical data of secondary syphilis patients. Gene ontology (GO) and KEGG enrichment analyses were performed on target genes of miR-142-3p.

Results

244 miRNAs exhibited at least 1.0-fold differential expression between secondary syphilis patients and healthy controls. The miRNAs were divided into three modules by WGCNA. The blue module was positively correlated with TPHA, TRUST, duration of disease, and erythema. And in the blue module, the expression of miR-142-3p was significantly higher in secondary syphilis patients than in healthy controls (p = 0.02), which is also close to the clinical features of secondary syphilis. GO and KEGG pathway analyses showed that these target genes of miR-142-3p are correlated with endocytosis and positive regulation of the apoptotic process.

Conclusion

The elevated miR-142-3p expression in PBMCs may play an important role in the immune response to T. pallidum infection and may be a potential biomarker for secondary syphilis.

Expression analysis of circulating miR-146a and miR-155 as novel biomarkers related to effective immune responses in human cystic echinococcosis

Cystic echinococcosis, an important zoonotic disease, is caused by Echinococcus granulosus. MicroRNAs are a small group of single-stranded noncoding RNAs, which play an effective role in biological processes. This study aimed at comparing the expression levels of miR-146a and miR-155 in the plasma of patients with hydatidosis and healthy individuals. A group of 20 patients with hydatid cyst formed a study group and 20 healthy individuals with no known chronic diseases formed a control group. Plasma samples were collected from hydatidosis patients as well as sex- and age-matched healthy volunteers. After that, RNA extraction and cDNA synthesis were done and the expression levels of miR-146a and miR-155 were determined by quantitative real-time polymerase chain reaction (PCR) for both groups. The results indicated that the level of miR-146a increased in all patients with hydatidosis compared to the control group. Also, the level of miR-155 increased in all hydatidosis patients, but no correlation was observed in the level of miR-155 between the two groups. The results also revealed that miR-146a and miR-155 upregulation in the plasma leads to the development of novel biomarkers for echinococcosis. One of the reasons for the increase of miRNAs in hydatidosis may be their role in modulating the immune system. These miRNAs are likely to be considered as one of the most important biomarkers in determining the severity of hydatidosis.

miR-155 and miR-146a collectively regulate meningitic Escherichia coli infection-mediated neuroinflammatory responses

Background

Escherichia coli is the most common Gram-negative bacterium causing meningitis, and E. coli meningitis is associated with high mortality and morbidity throughout the world. Our previous study showed that E. coli can colonize the brain and cause neuroinflammation. Increasing evidence supports the involvement of miRNAs as key regulators of neuroinflammation. However, it is not clear whether these molecules participate in the regulation of meningitic E. coli-mediated neuroinflammation.

Methods

The levels of miR-155 and miR-146a, as well as their precursors, in E. coli-infected astrocytes were measured using quantitative real-time PCR (qPCR). Overexpression and knockdown studies of miR-155 and miR-146a were performed to observe the effects on bacterial loads, cytokines, chemokines, and NF-κB signaling pathways. Bioinformatics methods were utilized to predict the target genes, and these target genes were validated using qPCR, Western blotting, and luciferase reporter system. In vivo knockdown of miR-155 and miR-146a was carried out to observe the effects on bacterial loads, inflammatory genes, astrocyte activation, microglia activation, and survival in a mouse model.

Results

The levels of miR-155, miR-146a, and their precursors were significantly increased in astrocytes during E. coli infection. miR-155 and miR-146a were induced by the NF-κB-p65 signaling pathway upon infection. Overexpressing and inhibiting miR-155 and miR-146a in astrocytes did not affect the bacterial loads. Further, the in vitro overexpression of miR-155 and miR-146a suppressed the E. coli-induced inflammatory response, whereas the inhibition of miR-155 and miR-146a enhanced it. Mechanistically, miR-155 inhibited TAB2, and miR-146a targeted IRAK1 and TRAF6; therefore, they functioned collaboratively to modulate TLR-mediated NF-κB signaling. In addition, both miR-155 and miR-146a could regulate the EGFR–NF-κB signaling pathway. Finally, the in vivo suppression of E. coli-induced miR-155 and miR-146a further promoted the production of inflammatory cytokines, aggravated astrocyte and microglia activation, and decreased mouse survival time, without affecting the bacterial loads in the blood and brain.

Conclusions

E. coli infection induced miR-155 and miR-146a, which collectively regulated bacteria-triggered neuroinflammatory responses through negative feedback regulation involving the TLR-mediated NF-κB and EGFR–NF-κB signaling pathways, thus protecting the central nervous system from further neuroinflammatory damage.

Efficient antisense inhibition reveals microRNA-155 to restrain a late-myeloid inflammatory programme in primary human phagocytes

A persisting obstacle in human immunology is that blood-derived leukocytes are notoriously difficult to manipulate at the RNA level. Therefore, our knowledge about immune-regulatory RNA-networks is largely based on tumour cell-line and rodent knockout models, which do not fully mimic human leukocyte biology. Here, we exploit straightforward cell penetrating peptide (CPP) chemistry to enable efficient loss-of-function phenotyping of regulatory RNAs in primary human blood-derived cells. The classical CPP octaarginine (R8) enabled antisense peptide-nucleic-acid (PNA) oligomer delivery into nearly 100% of human blood-derived macrophages without apparent cytotoxicity even up to micromolar concentrations. In a proof-of-principle experiment, we successfully de-repressed the global microRNA-155 regulome in primary human macrophages using a PNA-R8 oligomer, which phenocopies a CRISPR-Cas9 induced gene knockout. Interestingly, although it is often believed that fairly high concentrations (μM) are needed to achieve antisense activity, our PNA-R8 was effective at 200 nM. RNA-seq characterized microRNA-155 as a broad-acting riboregulator, feedback restraining a late myeloid differentiation-induced pro-inflammatory network, comprising MyD88-signalling and ubiquitin-proteasome components. Our results highlight the important role of the microRNA machinery in fine-control of blood-derived human phagocyte immunity and open the door for further studies on regulatory RNAs in difficult-to-transfect primary human immune cells.

microRNA-128 inhibits the inflammatory responses by targeting TAB2 in miiuy croaker, Miichthysmiiuy

The inflammatory response is a self-defense process that fights the pathogen invasion by eliminating harmful stimuli. However, excessive inflammation may disrupt immune homeostasis, even causing chronic inflammation or autoimmune diseases. MicroRNAs (miRNAs) are a crucial regulator that can negatively regulate gene expression and participate in multiple biological processes of growth, development, and immune response in organisms. However, the miRNA-mediated modulation networks of inflammatory responses remain largely unclear in lower vertebrates. In this study, miR-128 was identified as a negative regulator to participate in the NF-κB signaling pathway by targeting TAB2 in miiuy croaker. First, we predicted target genes of miR-128 through the bioinformatics software programs and found that TAB2 is a direct target of miR-128. We also found that miR-128 can inhibit TAB2 expression at the mRNA and protein levels. Besides, upon LPS stimulation, miR-128 inhibits the expression of inflammatory cytokines by targeting TAB2 to avoid excessive inflammation. Particularly, we found that miR-128 can regulate TAB2-mediated NF-κB signaling pathways. In summary, our results indicate that miR-128 plays a critical role in suppressing inflammatory responses by regulating the TAB2-mediated NF-κB signaling pathway in miiuy croaker.

MicroRNA Modulation of Host Immune Response and Inflammation Triggered by Helicobacter pylori

Helicobacter pylori (H. pylori) remains the most-researched etiological factor for gastric inflammation and malignancies. Its evolution towards gastric complications is dependent upon host immune response. Toll-like receptors (TLRs) recognize surface and molecular patterns of the bacterium, especially the lipopolysaccharide (LPS), and act upon pathways, which will finally lead to activation of the nuclear factor-kappa B (NF-kB), a transcription factor that stimulates release of inflammatory cytokines. MicroRNAs (MiRNAs) finely modulate TLR signaling, but their expression is also modulated by activation of NF-kB-dependent pathways. This review aims to focus upon several of the most researched miRNAs on this subject, with known implications in host immune responses caused by H. pylori, including let-7 family, miRNA-155, miRNA-146, miRNA-125, miRNA-21, and miRNA-221. TLR-LPS interactions and their afferent pathways are regulated by these miRNAs, which can be considered as a bridge, which connects gastric inflammation to pre-neoplastic and malignant lesions. Therefore, they could serve as potential non-invasive biomarkers, capable of discriminating H. pylori infection, as well as its associated complications. Given that data on this matter is limited in children, as well as for as significant number of miRNAs, future research has yet to clarify the exact involvement of these entities in the progression of H. pylori-associated gastric conditions.

Dysregulation of genes and microRNAs in localized aggressive periodontitis

AIM

Previous data from our laboratory have demonstrated that localized aggressive periodontitis (LAP) patients produce elevated levels of pro-inflammatory cytokines in response to TLR4 and TLR2 ligation compared to unrelated and periodontally healthy controls (HC). The aim of the present work is to evaluate the contribution of TLR-related gene expression and miRNA regulation in LAP disease.

MATERIAL AND METHODS

Peripheral blood mononuclear cells (PBMCs) from LAP and health control (HC) patients were isolated. Gene and miRNA expression involved in TLR signalling pathway and immunopathology were evaluated in unstimulated PBMCs by real-time PCR (RT-PCR).

RESULTS

TICAM-1 (TRIF), FOS, IRAK1, TLR2 and CCL2 genes and the miRNAs miR-9-5p, miR-155-5p and 203a-3p, miR-147a, miR-182-5p and miR-183-5p were significantly up-regulated in LAP compared to HC.

CONCLUSIONS

Most of the genes and miRNAs overexpressed here are directly or indirectly related to immune response and inflammation. This profile supports our previous findings that suggests LAP patients have a "hyper-responsive" phenotype upon activation of TLR pathway by periodontal pathogens.

DsRNA induction of microRNA-155 disrupt tight junction barrier by modulating claudins

Background

The impaired barrier function of the airway epithelium due to RNA virus infection is closely related to the development and exacerbation of allergic airway inflammation.

Objective

In this study, we investigated the roles of microRNAs on the mechanisms of double-stranded RNA (dsRNA)-induced epithelial barrier dysfunction.

Methods

16HBE14o- human bronchial epithelial cells were grown to confluence on Transwell inserts and exposed to poly-I:C. We studied epithelial barrier function by measuring transepithelial electrical resistance and paracellular flux of fluorescent markers and structure of tight junctions by immunofluorescence microscopy.

Results

Poly-I:C treated 16HBE14o- cells increased paracellular permeability. Knockdown of Toll-like receptor 3 and TRIF abrogated these effects. The expression of microRNA-155 (miR-155) was increased by poly-I:C in dose-dependent manner. Transfection of mir155 mimics into 16HBE14o- cells increased permeability and inhibited tight junction formation. Transfection of miR-155 inhibitor suppressed poly-I:C-induced barrier disruption. Poly-I:C treatment significantly decreased the expression of claudin members—claudin-1, -3, -4, -5, -9, -11, -16, -18 and -19. Transfection of miR-155 mimics showed similar changing expression pattern of claudin members with those of poly-I:C treatment.

Conclusion

These results suggest that RNA virus infection can impair the epithelial barrier disruption mechanism by down-regulation of claudin members through the induction of miR-155.

IRF3 and IRF8 Regulate NF-κB Signaling by Targeting MyD88 in Teleost Fish

MyD88 is a conserved intracellular adaptor, which plays an important role in the innate immune system. MyD88 transmits signals for downstream of toll-like and IL-1 receptors to activate NF-κB signaling pathway, which is tightly controlled in the immune response to maintain immune intensity and immune homeostasis at different stages. NF-κB signaling pathway has been extensively studied in mammals, but regulatory molecular mechanism is still unclear in teleost fish. We determined that IRF3 and IRF8 can regulate MyD88-mediated NF-κB signaling pathway in fish. Interestingly, MyD88 is precisely regulated by IRF3 and IRF8 through the same mechanism but in completely opposite ways. IRF3 promotes MyD88-mediated NF-κB signaling pathway, whereas IRF8 inhibits the signaling pathway. MyD88 is regulated via ubiquitin-proteasome degradation, whereas IRF3 or IRF8 inhibited or promoted MyD88 degradation in this pathway. Specifically, in the early stage of lipopolysaccharide (LPS) stimulation or Vibrio infection, up-regulation of IRF3 and down-regulation of IRF8 eventually increased MyD88 expression to activate the NF-κB signaling pathway to trigger immune response. In the late stage of stimulation, down-regulated IRF3 and up-regulated IRF8 synergistically regulate the expression of MyD88 to a normal level, thus maintaining the immune balance of homeostasis and preventing serious damage from persistent over-immunization. This study presents information on Myd88-NF-κB signaling pathway in teleost fish and provides new insights into its regulatory mechanism in fish immune system.

δ-Opioid Receptors, microRNAs, and Neuroinflammation in Cerebral Ischemia/Hypoxia

Hypoxia and ischemia are the main underlying pathogenesis of stroke and other neurological disorders. Cerebral hypoxia and/or ischemia (e.g., stroke) can lead to neuronal injury/death and eventually cause serious neurological disorders or even death in the patients. Despite knowing these serious consequences, there are limited neuroprotective strategies against hypoxic and ischemic insults in clinical settings. Recent studies indicate that microRNAs (miRNAs) are of great importance in regulating cerebral responses to hypoxic/ischemic stress in addition to the neuroprotective effect of the δ-opioid receptor (DOR). Moreover, new discovery shows that DOR can regulate miRNA expression and inhibit inflammatory responses to hypoxia/ischemia. We, therefore, summarize available data in current literature regarding the role of DOR and miRNAs in regulating the neuroinflammatory responses in this article. In particular, we focus on microglia activation, cytokine production, and the relevant signaling pathways triggered by cerebral hypoxia/ischemia. The intent of this review article is to provide a novel clue for developing new strategies against neuroinflammatory injury resulting from cerebral hypoxia/ischemia.

MicroRNA exporter HuR clears the internalized pathogens by promoting pro-inflammatory response in infected macrophages

HuR is a miRNA derepressor protein that can act as miRNA sponge for specific miRNAs to negate their action on target mRNAs. Here we have identified how HuR, by inducing extracellular vesicles‐mediated export of miRNAs, ensures robust derepression of miRNA‐repressed cytokines essential for strong pro‐inflammatory response in activated mammalian macrophages. Leishmania donovani, the causative agent of visceral leishmaniasis, on the contrary alters immune response of the host macrophage by a variety of complex mechanisms to promote anti‐inflammatory response essential for the survival of the parasite. We have found that during Leishmania infection, the pathogen targets HuR to promote onset of anti‐inflammatory response in mammalian macrophages. In infected macrophages, Leishmania also upregulate protein phosphatase 2A that acts on Ago2 protein to keep it in dephosphorylated and miRNA‐associated form. This causes robust repression of the miRNA‐targeted pro‐inflammatory cytokines to establish an anti‐inflammatory response in infected macrophages. HuR has an inhibitory effect on protein phosphatase 2A expression, and mathematical modelling of macrophage activation process supports antagonistic miRNA‐modulatory roles of HuR and protein phosphatase 2A which mutually balances immune response in macrophage by targeting miRNA function. Supporting this model, ectopic expression of the protein HuR and simultaneous inhibition of protein phosphatase 2A induce strong pro‐inflammatory response in the host macrophage to prevent the virulent antimonial drug‐sensitive or drug‐resistant form of L. donovani infection. Thus, HuR can act as a balancing factor of immune responses to curtail the macrophage infection process by the protozoan parasite.

Targeting cell signaling in allergic asthma

Asthma is chronic inflammation of the airways characterized by airway hyper-responsiveness, wheezing, cough, and dyspnea. Asthma affects >350 million people worldwide. The Th2 immune response is a major contributor to the pathophysiology of asthma. Targeted therapy modulating cell signaling pathways can be a powerful strategy to design new drugs to treat asthma. The potential molecular pathways that can be targeted include IL-4-IL-13-JAK-STAT-MAP kinases, adiponectin-iNOS-NF-κB, PGD2-CRTH2, IFNs-RIG, Wnt/β-catenin-FAM13A, FOXC1-miR-PI3K/AKT, JNK-Gal-7, Nrf2-ROS, Foxp3-RORγt, CysLTR, AMP, Fas-FasL, PTHrP/PPARγ, PAI-1, FcɛRI-LAT-SLP-76, Tim-3-Gal-9, TLRs-MyD88, PAR2, and Keap1/Nrf2/ARE. Therapeutic drugs can be designed to target one or more of these pathways to treat asthma.

The Inducible microRNA-21 Negatively Modulates the Inflammatory Response in Teleost Fish via Targeting IRAK4

Eradication of bacterial infection requires timely and appropriate immune and inflammatory responses, but excessive induction of inflammatory cytokines can cause acute or chronic inflammatory disorders. Thus, various layers of negative regulators and mechanisms are needed to ensure maintenance of the homeostasis for the immune system. miRNAs are a family of small non-coding RNAs that emerged as significant and versatile regulators involved in regulation of immune responses. Recently, the molecular mechanisms of miRNA in host-pathogen interaction networks have been extensively studied in mammals, whereas the underlying regulatory mechanisms in fish are still poorly understood. In this study, we identify miR-21 as a negative regulator of the teleost inflammatory response. We found that lipopolysaccharide and Vibrio anguillarum significantly upregulated the expression of fish miR-21. Upregulated miR-21 suppresses LPS-induced inflammatory cytokine expression by targeting IL-1 receptor-associated kinase 4 (IRAK4), thereby avoiding excessive inflammatory responses. Furthermore, we demonstrated that miR-21 regulates inflammatory responses through NF-κB signaling pathways. The collective findings indicate that miR-21 plays a regulatory role in host-pathogen interactions through IRAK4-mediated NF-κB signaling pathway.

Clear Victory for Chlamydia: The Subversion of Host Innate Immunity

As obligate intracellular bacterial pathogens, members of the Chlamydia genera are the pivotal triggers for a wide range of infections, which can lead to blinding trachoma, pelvic inflammation, and respiratory diseases. Because of their restricted parasitism inside eukaryotic cells, the pathogens have to develop multiple strategies for adaptation with the hostile intracellular environment—intrinsically present in all host cells—to survive. The strategies that are brought into play at different stages of chlamydial development mainly involve interfering with diverse innate immune responses, such as innate immune recognition, inflammation, apoptosis, autophagy, as well as the manipulation of innate immune cells to serve as potential niches for chlamydial replication. This review will focus on the innate immune responses against chlamydial infection, highlighting the underlying molecular mechanisms used by the Chlamydia spp. to counteract host innate immune defenses. Insights into these subtle pathogenic mechanisms not only provide a rationale for the augmentation of immune responses against chlamydial infection but also open avenues for further investigation of the molecular mechanisms driving the survival of these clinically important pathogens in host innate immunity.

Abnormal Expression of DICER1 Leads to Dysregulation of Inflammatory Effectors in Human Synoviocytes

Dysregulation of multiple microRNAs widely takes place during rheumatoid arthritis (RA) and experimental arthritides. This study is performed to explore the possible mechanism underlying DICER1 deficiency-mediated inflammation in human synoviocytes SW982. Firstly, RNAi of DICER1 led to increased COX2, MMP3, and MMP13 protein production, while DICER1 overexpression could reduce MMP13 expression. Secondly, the increase of IL-8 and decrease of TGF-β1 and TIMP1 were determined in the supernatant derived from DICER1 siRNA-treated cells, while DICER1 overexpression was found capable to reverse this effect. Ingenuity pathway analysis (IPA) software predicted that the Dicer1 deficiency-induced dysregulated cytokines in synoviocytes could possibly lead to the inflammatory disorders in the synovial tissue. Moreover, DICER1 deficiency could also reduce apoptosis, while DICER1 overexpression was found to decrease the proliferation and enhance apoptosis. In addition, DICER1 deficiency could lower the expression of multiple RA-related miRNAs such as miR-155. Meanwhile, DICER1 overexpression could rescue their low expression levels. And then, gain or loss of miR-155 function could regulate the protein levels of MMP3 and MMP13. These results indicated that DICER1 might play its role through regulating its downstream RA-related miRNAs. Our data demonstrated that DICER1 deficiency could cause multiple proinflammatory events in human synoviocytes SW982. This mechanism study might provide the possible target molecule to modify the inflammatory destruction and overproliferation in synoviocytes.

Taenia crassiceps-Excreted/Secreted Products Induce a Defined MicroRNA Profile that Modulates Inflammatory Properties of Macrophages

Helminth parasites modulate immune responses in their host to prevent their elimination and to establish chronic infections. Our previous studies indicate that Taenia crassiceps-excreted/secreted antigens (TcES) downregulate inflammatory responses in rodent models of autoimmune diseases, by promoting the generation of alternatively activated-like macrophages (M2) in vivo. However, the molecular mechanisms triggered by TcES that modulate macrophage polarization and inflammatory response remain unclear. Here, we found that, while TcES reduced the production of inflammatory cytokines (IL-6, IL-12, and TNFα), they increased the release of IL-10 in LPS-induced bone marrow-derived macrophages (BMDM). However, TcES alone or in combination with LPS or IL-4 failed to increase the production of the canonical M1 or M2 markers in BMDM. To further define the anti-inflammatory effect of TcES in the response of LPS-stimulated macrophages, we performed transcriptomic array analyses of mRNA and microRNA to evaluate their levels. Although the addition of TcES to LPS-stimulated BMDM induced modest changes in the inflammatory mRNA profile, it induced the production of mRNAs associated with the activation of different receptors, phagocytosis, and M2-like phenotype. Moreover, we found that TcES induced upregulation of specific microRNAs, including miR-125a-5p, miR-762, and miR-484, which are predicted to target canonical inflammatory molecules and pathways in LPS-induced BMDM. These results suggest that TcES can modulate proinflammatory responses in macrophages by inducing regulatory posttranscriptional mechanisms and hence reduce detrimental outcomes in hosts running with inflammatory diseases.

Vibrio cholerae derived outer membrane vesicles modulate the inflammatory response of human intestinal epithelial cells by inducing microRNA-146a

The small intestinal epithelium of Vibrio cholerae infected patients expresses the immunomodulatory microRNAs miR-146a and miR-155 at acute stage of disease. V. cholerae release outer membrane vesicles (OMVs) that serve as vehicles for translocation of virulence factors including V. cholerae cytolysin (VCC). The aim was to investigate whether OMVs, with and/or without VCC-cargo could be responsible for induction of microRNAs in intestinal epithelial cells and thereby contribute to immunomodulation. Polarized tight monolayers of T84 cells were challenged with OMVs of wildtype and a VCC deletion mutant of the non-O1/non-O139 (NOVC) V. cholerae strain V:5/04 and with soluble VCC. OMVs, with and without VCC-cargo, caused significantly increased levels of miR-146a. Increase was seen already after 2 hours challenge with OMVs and persisted after 12 hours. Challenge with soluble VCC caused significant increases in interleukin-8 (IL-8), tumour necrosis factor-α (TNF-α), CCL20, IL-1β, and IRAK2 mRNA levels while challenge with OMVs did not cause increases in expression levels of any of these mRNAs. These results suggest that V. cholerae bacteria release OMVs that induce miR-146a in order to pave the way for colonization by reducing the strength of an epithelial innate immune defence reaction and also preventing inflammation in the mucosa that factors like VCC can evoke.

The influence of the Chuyou Yuyang granule on the Toll-like receptor/nuclear factor-κB signal pathway in Helicobacter pylori-positive peptic ulcer patients

BACKGROUND

The cure rate of Helicobacter pylori (HP)-positive peptic ulcer has appeared to downward trend, and the resistance of the ulcer relapse has become a hot issue.

METHODS

Hematoxylin and eosin staining was used to detect the repair of the damaged tissues in patients after treatment with the Chuyou Yuyang granule (CYYY). Elisa was used to analyze the expression of cytokine interleukin 18 (IL-18) and tumor necrosis factor α (TNF-α) in the patients' serum. Western blot analysis was used to explore the mechanism of the CYYY. Reverse-transcription polymerase chain reaction (RT-PCR) was used to detect the expression of microRNA-155a (miR-155a) and miR-146a in the blood of the patients and to confirm whether CYYY could cure peptic ulcer through regulation of miR-155a and miR-146a.

RESULTS

The damaged gastric mucosal tissues of ulcer patients were significantly repaired by treating with CYYY. The pro-inflammatory cytokine IL18 and TNF-α were notably repressed after treating with CYYY. In addition, CYYY played a key role in regulation of the Toll-like receptor (TLR4)/nuclear factor-κB (NF-κB) signal pathway and the expression of miR-155a and miR-146a.

CONCLUSION

CYYY was a highly effective therapeutic method for peptic ulcer patients by inhibiting the activation of the TLR4/NF-κB signal pathway and suppressing the expression of miR-155a and miR-146a.

Effects of restrictions on maternal feed intake on the immune indexes of umbilical cord blood and liver Toll-like receptor signaling pathways in fetal goats during pregnancy

Background

Liver has important immune function during fetal development and after birth. However, the effect of maternal malnutrition on immune function of the fetal liver is rarely reported. In this study, twelve pregnant goats (Xiangdong black goat, at d 45 of gestation) were assigned to the control group (fed 100% of nutritional requirements) and the restriction group (fed 60% of the intake of the control group) during gestation from d 55 to 100. Fetal goats were harvested at d 100 of gestation and immune indexes and amino acid profiles of the umbilical cord blood and liver Toll-like receptors (TLRs) signaling pathways were measured.

Results

Maternal body weight in the restriction group was lower than the control group (P < 0.05). Maternal feed intake restriction decreased (P < 0.05) heart weight, heart index, alkaline phosphatase and serum amyloid protein A in the umbilical cord blood (UCB). Moreover, only histidine was decreased in the restricted group (P = 0.084), and there were no differences in other amino acids contents in the UCB between the two groups (P > 0.05). The TLR2 and TLR4 mRNA expression in the fetal liver in the restriction group was greater (P < 0.05) than that in the control group. Furthermore, the mRNA expression levels of myeloid differentiation primary response 88 (MyD88), TNF receptor associated factor 6, nuclear factor kappa B subunit 1, NFKB inhibitor alpha, IFN-β, TGF-β, TNF-α and IL-1β in the restricted group were upregulated (P < 0.05), and the expression of TLR3 (P = 0.099) tended to be higher in the restricted group. However, protein levels of TLR2, TLR4, IκBα, phosphorylated IκBα, phosphorylated IκBα/total IκBα, TRIF and MyD88 were not affected (P > 0.05) by maternal intake restriction.

Conclusions

These results revealed that the restriction of maternal feed intake influenced the development of heart and hepatic protein synthesis at the acute phase of fetal goats and upregulated the mRNA expression of genes involved in MyD88-dependent signaling pathways and of target cytokines.

MicroRNA-155 promotes pro-inflammatory functions and augments apoptosis of monocytes/macrophages during Vibrio anguillarum infection in ayu, Plecoglossus altivelis

Upon recognition of pathogen-associated molecular patterns by pattern-recognition receptors, immune cells are recruited, and multiple antibacterial/viral signaling pathways are activated, leading to the production of immune-related cytokines, chemokines, and interferons along with further activation of the adaptive immune response. MicroRNAs (miRs) play essential roles in regulating such immune signaling pathways, as well as the biological activities of immune cells; however, knowledge regarding the roles of miRs in the immune-related function of monocytes/macrophages (MO/MΦ) remains limited in teleosts. In the present study, we addressed the effects of miR-155 on Vibrio anguillarum-infected MO/MΦ. Our results showed that miR-155 augmented MO/MΦ expression of proinflammatory cytokines and attenuated the expression of anti-inflammatory cytokines. Additionally, the phagocytosis and bacteria-killing abilities of these cells were boosted by miR-155 administration, which also promoted M1-type polarization but inhibited M2-type polarization. Furthermore, the V. anguillarum-infection-induced apoptosis was also enhanced by miR-155 mimic transfection, which might have been due to excessive inflammation or the accumulation of reactive oxygen species. These results represent the first report providing a detailed account of the regulatory roles of miR-155 on MO/MΦ functions in teleosts and offer insight into the evolutionary history of miR-155-mediated regulation of host immune responses.

MiRNA as biomarker for uveitis - A systematic review of the literature

AIM

A systematic review of miRNA profiling studies in uveitis.

METHODS

Literature search strategy - Pubmed central central database, using miRNA/microRNA and intraocular inflammation/uveitis as keywords.

RESULTS

We found twenty publications regarding the experimental and clinical use of miRNA in uveitis, published between 2011 and 2018.

CONCLUSION

The publications regarding the role of miRNA in uveitis are very scarce, but provide some valuable information about the potential new mechanisms in uveitis. Some of the identified miRNAs in different uveitis entities could serve as a biomarker of intraocular inflammation. Possible candidate miRNAs could be let-7e, miRNA-1, miR-9-3, miR-20a-5p, miR-23a, mir-29a-3p, miR-140-5p, miR-143, miR-146a and miR-146a-5p, miR-155, miR-182 and miR-182-5p, miR-196a2, miR-205, miR-223-3p, miR-301a. MiR-146a, miR-146a-5p, miR-155, miR-182, miR-223-3p, have been found to be possibly associated with uveitis disease in both, human and animal species.

Regulation of TLR signaling pathways by microRNAs: implications in inflammatory diseases

The control of the immune response during the development of some diseases is crucial for the maintenance or restoration of homeostasis. Several mechanisms can initiate inflammation, one of which is the activation of toll-like receptors (TLRs), necessary to initiate the immune response to eliminate an infection. However, inappropriate activation can compromise immunological homeostasis, leading to pathologies such as autoimmune diseases, chronic inflammation, and even cancer. Regulatory mechanisms that intervene in the initiation or modulation of inflammation include microRNAs (miRNAs), which have emerged as key post-transcriptional regulators of proteins involved in distinct cellular processes, such as regulation of the immune response. The focus of this review is on the diverse roles of miRNAs in the regulation of TLR-signaling pathways by targeting multiple molecules, including TLRs, the signaling proteins and cytokines induced by TLRs. It will also address the relationships of these molecules with some diseases that involve inflammation such as rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), cancer, as well as bacterial or viral infections.